Concentration of ores



June 6 1939. c. T. MORRISON ET AL 2,

' CONCENTRATION OF ORES Filed July 27, 1935; 2 Sheets-Sheet 1 .n" aummlr I I I will... mr' M" H} I I nn hmam Z/f I arZes 2710172270 June 6,1939.

c. 'i'. MORRISON r AL 2,161,425

CONCENTRATION oF'onEs Filed July 27, 1935 2 Sheets-Sheet 2 yflmw,

Patented June 6, 1939 PATENT oFFIcE CONCENTRATION OF ORES Charles '1.Morrison and Harry T. Eastman,

Chicago, 111.

Application July 2'7,

, 7 Claims.

This invention relates to the concentration of ores and particularly tothe concentration of placer ores which contain metallic particles or"metalliferous particles of substantially greater specific gravity thanthe gangue with which they are associated. The invention is, however,notlimited to its application to placer ores since it may be applied toores which are ground or comminuted so as to liberate metallic ormetalliferous particles of greater specific gravity than the associatedgangue.

One of the objects of the present invention is ,to provide a method of.concentrating ore which can be operated without the use of water,yielding the valuable ore content in highly concentrated 'form by theaid of purely mechanical operations.

A further object-of the invention is to provide a purely vibratorymethod of concentrating ores. A further object of the invention is toprovide an inexpensive andefiective apparatus for the concentration ofores in accordance with such methods.

Other objects, advantages and capabilities of the invention will appearfrom the following description of the method and apparatus in which itmay be practiced, taken in conjunction with Y the accompanyingdrawingswhich illustrate such an apparatus.

In the drawings:

Figure 1 is a plan view .of the apparatus.

Fig.2 is a sectional elevational view therethrough, taken on the line 22of Fig. l;

. Fig. 3 is an elevational view of the apparatus;

Fig. 4 is'a sectional"elevational detail view, taken on the line 44 ofFig.5 showing the manner in which a hammer is mounted;

Fig. 5;is asectional plan detail view; Fig.:6-is a sectionaldetail'view, taken on the line 6'5 of Fig. 5, and W i Fig. 7 is asectional detail view showing the closure of the hopper in a mannersimilar to Fig. 2, but on a substantially larger scale.

Referring to the drawings, the reference numeral ll] designates a hoppercomprising four vertical sides H and four sloping bottom plates l2which, converge to a rectangular or square opening l3. The hopper issupported upon long skids 14 which enable itto be transported from placeto place as the work progresses.

Fourlegs I5 are secured to the skids l4 and serve to support the hopperIll at an elevated position- The legs I5 are preferably located atthecorners of the hopper and project through the bottom of the hopper andterminate at an intermediateheight on the sides ll. These legs 1935,Serial No. 33,484

may be of any suitable shape and are surmounted I t by inclined platesl6 which guide material resting thereon downwardly towards the bottom ofthe hopper. The legs I5 are preferably bolted or tied through the sidewalls H to channel members l1 which are arranged around the exterior ofthe sides H at the lower end thereof. The upper edges of the walls IIare reinforced by angle irons l8, which are best shown in Figs. 1 and 2.The whole structure is braced by diagonal tie rods I9 which are locatedimmediately below the sides II and are connected to the legs l5, as bestshown in Fig. 3.

The opening I3 is closed by a hopper-like door 20 which corresponds tothe shape of the opening l3. This door is preferably mounted by means ofhinges 2| upon one of the bottom sections I2. It may be secured inclosed position by means of a bolt or pin 22. As best shown in Fig. 7,the bottom sections l2 overlap the adjacent sections of the hopper-likeclosure 2!! so that no pocket is formed and no impediment to the freedescent of the heavy metal or metalliferous particles is presented atthepoints of contact of the closure 20 with the hopper 10. At itscenter, and consequently at its lowest point, the closure 26 is providedwith a relatively small threaded outlet 23. This outlet may be mountedon the closure 20 by means of flanges 24 which underlie the wallportions of the closure 20.

The outlet 23 is normally closed by means of a threaded plug 25. t Thethreaded portions of the outlet 23 and the plug 25 are cut away atintervals around the circumference, as indicated at 26, so that the plugmay be securely mounted in position by mere insertion and turningthrough a fraction of a revolution, after the manner common in the caseof breech blocks of large guns. The material to be treated in the hoppermay be supplied thereto in any suitable way. It is preferred, however,to supply this material by means of an overhead conveyor 21 which maysuitably extend over a battery of apparatus of the type just described.A baffle 28 suitably located above the hopper l0 causes the material tobe delivered from the conveyor 21 into the hopper. As will hereinafterbe more fuliy described, the valuable, highly concentrated fraction ofthe ore moves gradually downward and finally rests immediately above theplug 25 or in close proximity thereto. Consequently, by merely removingthe plug 25 practically all of the valuable concentrate passesdownwardly through the outlet 21% into a suitable reservoir held inposition to receive same. After the concentrate has thus been removed,the closure is opened and the remaining contents of the hopper aredischarged. They may suitably be deposited upon a conveyor 29 andremoved to a suitable place. It will readily be understood that theconveyor 29 may extend below the openings I3 of a row of hoppers, justas the conveyor 21 is arranged to supply such row of hoppers.

The means whereby the highly effective state of vibration of the hopperand its contents is created and maintained, will now be described. Thesemeans comprise air hammers 30 which are distributed'on the underside ofthe bottom of the hopper l0. Each air hammer 30 is supported from thebottom by means of an inverted tripod 3| which has three legs 32, asbest shown in Figs. 4 and 5. The legs 32 may suitably be formed of angleiron and at their upper ends they are welded or otherwise suitablysecured to plates 3B which project upwardly from the plate 34.

After the air hammer has. been mounted in position, a securing pin 31 isscrewed into an appropriate opening in the plate 34 so that its upperend projects into contact with the shim plate 35 and-the base of the airhammer 30, as best seen in Fig. 6.

With reference to Fig. 5, it will be noted that the two pins 36 and thepin 31 are located at equal distances with reference to thecircumference of the air hammer-30 and shim. plate 35. The upper end ofthe hammer 30 is inserted into a cup-like percussion abutment 3B whichis invertedly mounted on the bottom plate I 2 of the hopper. Thepercussion abutment 38 is provided with a flat base which is secured bywelding or other suitable manner to said bottom plate. The percussionabutment 38 is provided with a horizontal surface which is adapted toreceive the impacts of the percussion member 39 of the hammer 30.Immediately above each percussion member 38 is mounted a vertical bar40, which may suitably be in the form of an angle iron. These bars areintended to serve as vibrating prongs communicating the impacts appliedby the hammers 30 to the abutment members 38, throughout the mass of theore contained in'the hopper. The angle irons 40 have their anglesdirected upwardly, relative to the slope of the bottom plates I2, 50that they form no pockets in which ore might collect.

The hammers 3B are supplied with compressed air by means of flexiblepipes 4|. which are connected to main supply pipe 42. It will readily beunderstood that when air is supplied by the pipe 42, each air hammer isautomatically set into rapid and violent operation. These hammers,together with the prongs 40, are distributed over the bottom plates I2in the manner best seen in Fig. 1 so that every portion of the charge ofore within the hopper is subjected to vibration.

The present method is based upon our discovery that placer ores and alsoground or pulverized ores, which contain metallic or metalliferousparticles of higher specific gravity than the associated gangue, can beclassified and concentrated without the aid of water by merelymaintaining them in a highly effective state of rapid vibration. We havefound that the high speed vibrations engendered by the impacts caused byair hammers of well known and conventional type are highly effective forthis purpose and cause the heavy metallic or metalliferous particles .todescend through the body of ore towards the lower portion thereof. Ifthe vibratory process is continued for a sufficient period of timepractically all the heavy metallic and metalliferous particles will worktheir way to the bottom of the mass.

The period of time during which the violent and rapid vibration must bemaintained depends upon many factors such as the nature of theconcentrate, the degree of concentration, the size of the hopper, and soforth. In the case of placer ores using the number of hammers shown inthe drawings and with a hopper of side length of about eighteen feet, ahighly satisfactory concentration of placer ores can be effected betweenone-half and two hours. At the end of the treatment the greater part ofthe gold contained'in the placer ore will be located at or near theoutlet 23. The plug 25 is removed and about two bushels of ore ispermitted to pass through the outlet 23 into a suitable receptacle. Thismaterial contains practically all the concentrate and it may be furtherconcentrated in anydesired manner.

In practicing the invention on a commercial scale, it is preferred tohave a row of hoppers of the general type described above, all suppliedby an upper conveyor 21. The movable baffle 28 enables the supply of oreto be diverted into any one hopper. After the hopper is filled, thehammers are started and the dry gravity concentration is conducted forthe appropriate length of time. After the concentrated ore is removed inthe manner previously described, the closure 20 is opened and the.remainder of the charge is permitted to pass on to the conveyor 29 whichremoves it to a suitable dumping place.

During the operation of our method the whole body of the ore appears tobe in a state of violent vibration. The particles move or danceindividually and the movement can be felt by the hand. During thevibratory movements of the individual particles, the heavy gold-bearingand other metallic and metalliferous particles seem to move forward to agreater extent than do the contiguous. gangue particles. This operationappears to be repeated indefinitely during the application of theviolent impacts which cause the individual particles of the ore toseparate sufficiently to'permit independent movement. of the particles.

It will be noted that our improved method is conducted without the aidof water and that it provides a highly effective method forconcentrating placer deposits which occur in desert country. Many suchdeposits have a small gold content and cannot be treated by existingmethods on a commercial basis because of the lack of water on the onehand and the cost of transportation on the other hand. Our improvedmethod permits such deposits to be treated in situ, yielding high valueconcentrates which can be further concentrated on the location or'betransported to more suitable locations for recovery of the gold or othervaluable metals.

Although the invention has been disclosed in connection with thespecific detailsrof a preferred embodiment thereof, it must beunderstood that such details are not intended to be limitative of theinvention except in so far as set forth in the accompanying claims.

Having'thus described our invention, what we claim as new and desire tosecure by Letters Patent of the United States is:

1. An apparatus for concentrating ores comprising a hopper having abottom converging downwardly toward its center, a door at the 'center ofsaid bottom, an outlet mounted in said ,door, a plug closingsaidopening, a plurality of air hammers adapted to impact against the bottomof said hopper, inverted tripods secured to said bottom and supportingsaid hammers, and

prongs mounted on the upper side of said bottom in alignment with saidhammers.

2. The method of concentrating dry ore which comprises maintaining abody of dry ore particles in the form of an inverted cone, subjectingsaid body to high speed vibrations in the vertical direction, saidvibrations being of such intensity and rapidity that the metalliferousparticles are caused'to descend through the body towards the lower apexof the conical body, and

body and become concentrated thereat, and pre- 1 venting upward currentsof air through said body.

4. 'The method of concentrating dry ore which comprises placing said dryore particles in a downwardly converging hopper, applying re- I thevertical direction, maintaining said vibration with intensity andrapidity and for suflicient time to cause the heavymetallic andmetalliferous particles to descend towards the apical portion of thehopper, preventing upward currents of air through said ore particles,withdrawing a concentrated fraction of ore, and thereafter withdrawingthe remaining ore separate from said fraction.

5. An apparatus for concentrating ores comprising an imperforatedownwardly converging hopper having an outlet at its bottom, said hopperbeing adapted to retain a charge of ore for batch treatment, andmechanical means applying impacts to the hopper for maintaining saidhopper and its contents in a state of vibration in the verticaldirection of such speed and intensity that the heavy metalliferousparticles are caused to descend through the ore to the lowermost end ofthe hopper adjacent said outlet.

6. An apparatus for concentrating dry ores comprising a hopper having animperiorate wall in direct contact with the ores to be concentrated,means for applying impacts to the imperforate hopper wall to causevibrations in the vertical direction of such speed and intensity thatthe heavy metalliferous particles are caused to descend through the ore,and means mounted on said wall and extending upwardly into the ore spaceof the hopper for distributing said vibrations to the contents of thehopper.

'7. An apparatus for concentrating ores comprising an imperforate hopperhaving a sloping bottom, means for applying vibrations to said hopper,means within said hopper for distributing said vibrations to thecontents of the hopper, a door at the lowest portion of said bottom foremptying said hopper, an outlet mounted in said door for removingconcentrate from said hopper, and a closure for said outlet.

CHARLES T. MORRISON. HARRY T. EASTMAN.

